The body of a woman has been found on board the capsized cruise liner Costa Concordia, bringing the confirmed death toll to 12.

The woman, who was wearing a life jacket, was found by divers in a corridor on the fourth deck of the Costa Concordia, said coastguard commander, Cosimo Nicastro.

The body was brought to Giglio, the Tuscan island where the liner hit a reef and ran aground on 14 January. Twenty people are missing.

The discovery came as it emerged that the owners of the stricken ship are facing a multimillion-pound lawsuit from more than 100 passengers, and fears grew of a developing environmental disaster caused by leaking fuel.

Two US law firms and Italy's consumer association Codacons told the BBC they would be filing a suit against Costa Cruises on behalf of the crash victims in the next week.

Each of the 110 claimants will reportedly be seeking at least £100,000 in damages, with some asking for two or three times the minimum claim.

Costa Cruises, which is owned by the US-based Carnival Group, has blamed captain, Francesco Schettino, for last week's disaster.

The ship hit rocks off the coast of the Tuscan island of Giglio with more than 4,200 people on board a week ago.

The company accused Schettino of committing "grave errors of judgment" by steering the ship too close to Giglio on an "unauthorised manoeuvre".

Schettino is currently under house arrest suspected of manslaughter, which he denies.

But Mitchell Proner, a lawyer with US firm Proner & Proner, told the BBC that the owners could not pin all responsibility for the disaster on a "rogue captain".

"It's easy to say this captain acted alone," he said.

"There are indications that there have been regular route deviations in the past. There should have been safeguards on board, where were the alarms?

"At the time of the Titanic it might have been easy to say that radars didn't exist. Nowadays, with all the technology, it isn't. There had to be a failure in the system that allowed this to happen."

He said Proner & Proner in association with Codacons would file a lawsuit in Miami by Wednesday.

Passengers would be seeking compensation for ongoing medical care, loss of earnings as well as the psychological impact they had suffered while trying to escape the sinking ship, he added. Twenty people remain missing.

As the search for survivors resumed on Saturday, Italian coastguard officials said diesel, apparently from machinery aboard the ship, had been found in the sea nearby.

But coastguard spokesman Nicastro said there was no indication that any of the nearly half a million gallons of heavy fuel oil in the cruiser's double-bottomed tanks had leaked.

He described the diesel in the sea as "very light, very superficial" and seemingly under control.

"We must not forget that on that ship there are oils, solvents, detergents, everything that a city of four thousand people needs," said the head of Italy's civil protection agency, Franco Gabrielli, who is leading the rescue, search and anti-pollution efforts.

Boats equipped with machinery to remove the oil from the sea were being deployed, Italian officials told Italian TV.